The present invention relates to a separator tank assembly for a fluid compressor. More specifically, the present invention relates to a separator tank assembly used to scavenge lubricant from a separator element of a fluid compressor.
Conventional fluid compressors, such as a screw compressors, can become flooded with lubricant used to lubricate the component parts of the compressor. The lubricant, usually oil, frequently and undesirably leaks past the seals in the fluid compressor system and mixes with the compressed fluid stream. To remove the lubricant from the fluid stream, the compressed fluid/lubricant mixture is directed into a separator element of a separator tank, where the lubricant is separated out from the compressed fluid stream.
Separator elements typically have a perforated outer sleeve, a perforated inner sleeve, and a spun metal top flange. A separating media is sandwiched between the perforated outer sleeve and the perforated inner sleeve. An end cap or cover closes the discharge end of the whole assembly. When lubricant-laden fluid, such as oil-laden air, passes from outside the separator element assembly to inside the separator element assembly, the separating media entraps the droplets of lubricant in the fluid, and the compressed fluid exits the separator element assembly in a much less contaminated condition. In an air compressor, for example, treated air typically is 3 parts per million by weight. Meanwhile, the lubricant that has been separated from the compressed fluid drains down the inside and outside of the separator element. The lubricant that drains down the outside of the element simply runs back into the lubricant sump. The lubricant that drains downs the inside of the separator element has to be removed from the element; otherwise, the efficiency of separating media to remove lubricant from the fluid stream is affected.
The conventional way to remove lubricant from inside the separator element is to run an independent scavenge tube into the center of the separator element assembly. The scavenge tube is inserted through the end cap of the assembly and piped to a low pressure part of the lubricant/fluid circuit, usually before the compression phase. The scavenge tube ideally extends to the bottom of the separator element, on the inside of the element, and draws off the excess lubricant before it saturates the separating media and causes lubricant carryover.
Positioning the scavenge tube through the cover of the separator element assembly can be difficult. If the scavenge tube is too long, it can puncture the bottom of the separator element. If the scavenge tube is too short, it will not be effective to remove lubricant.
The invention alleviates the disadvantages present in conventional fluid compression systems by providing a separator element for use in a separator tank that has a scavenge tube integrally formed with the separator element. The separator element comprises a housing having a base and a sidewall structure. The housing preferably comprises a perforated outer sleeve, a perforated inner sleeve, and a separating media located between the inner and the outer sleeves. The separator element also comprises a support element permanently mounted to the housing. The separator element further comprises a scavenge tube fixed to the support element so that one end of the scavenge tube is located at a predetermined position relative to the base of the housing. Accordingly, once the separator element has been assembled, with the scavenge tube forming a component part of the separator element, there is no need for independent adjustment of the scavenge tube relative to the base of the separator element and, hence, no risk of making the scavenge tube too long or too short relative to the base.
In another aspect of the invention, the housing has a longitudinal central axis, and the support element fixes the scavenge element along the longitudinal central axis. In this manner, the scavenge tube is centralized in the separator element for maximum lubricant-scavenge efficiency. The support element can have a central portion and at least two arms extending from the central portion and attaching to the housing. The housing, in turn, can have a mounting section that extends inward from an inner surface thereof, so that at least a portion of the arms of the support element can be mounted to the mounting section. In this regard, the mounting section can form an annular shelf in the interior of the housing, perpendicular to the longitudinal central axis of the housing. The annular shelf can have a top surface, facing away from the base of the housing, and the portion of each of the at least two arms can be mounted to the top surface of the annular shelf.
A separator tank assembly for use in a fluid compression system in accordance with the invention comprises a separator element having a base, a support element mounted to the separator element, and a scavenge tube. The scavenge tube is fixed to the support element so that a first end of the scavenge tube is located at a predetermined position relative to the base of the separator element. The separator tank assembly also comprises a tank housing having an outer flange at a top end thereof. The tank housing is dimensioned to receive the separator element. The separator tank assembly further comprises a tank cover to attach to the outer flange of the tank housing. The tank cover has a cover orifice therethrough. The assembly additionally comprises an adapter extending through the cover orifice. The adapter has a first section to connect to a second end of the scavenge tube and a second section to connect to a line component of the fluid compression system.
The first section of the adapter can include a seal element, such as an O-ring, to engage an outer surface the scavenge tube. The adapter has an adapter orifice extending therethrough that communicates with a flow passage in the scavenge tube when the adapter is attached to the scavenge tube. The adapter also can include a valve positioned in the adapter orifice between the first section and the second section to restrict fluid flow in a direction from the second section to the first section. In addition, the second section of the adapter can include a fitting in the adapter orifice to restrict fluid flow in a direction from the first section to the second section through the orifice. This fitting can be press fit in the adapter orifice. Alternatively, the second section of the adapter can be machined to form the fitting. The fitting can have a tapered channel that tapers toward the first section of the adapter.
To mount the separator element in the separator tank housing, the separator element includes a flange extending out from a top end thereof opposite the base. This flange is positioned between the outer flange of the tank housing and the tank cover.
In still another aspect of the invention, an adapter assembly for placement in a cover of a separator tank of a fluid compression system comprises a first section to connect to a scavenge element of the separator tank, a second section to connect to a line component of the fluid compression system, and a an adapter orifice for fluid flow therethrough. A seal element is positioned in the first section to engage an outer surface the scavenge element. A valve is positioned in the adapter orifice between the first section and the second section to restrict fluid flow in a direction from the second section to the first section. A fitting is positioned in the adapter orifice in the second section of the adapter to restrict fluid flow through the adapter orifice.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.